He studied composition in Prague. Later he was a pupil of Richard Stöhr and Franz Schreker in Vienna and Berlin. During his stay in Vienna, he worked as a proofreader for Universal Edition. After returning to Bohemia and settling in Prague in 1923, he exerted a major influence on the Czech music life. His teaching work at, among others, Prague Conservatoire, was of international importance, and his students included such European modernists as Slavko Osterc, among others.
He began his experiments in quarter-tone music during his student years and became renowned as a pioneer in this field. Additionally, he developed the concept of 'liberated music' (Musik der Freiheit) and promoted the 'athematic style' in musical composition. He also contributed to the development of new musical instruments, including the quarter-tone piano (1925). One of his most significant works was the quarter-tone opera Mother (1927–29), which premiered in Munich in 1931. He also composed string quartets in various microtonal systems. His theoretical contributions include two fundamental works on harmony (from 1927 and 1942–43).
His composition—the Second String Quartet—was performed during the first official ISCM festival in Salzburg in 1923. He also played a key role in that organisation and its Czechoslovak branch, including as an international jury member at the ISCM festivals in 1927, 1928, and 1938 (as well as in 1958 and 1961).
Hába was also an active member of the Anthroposophical Society, maintaining close connections with its international structures. The influence of anthroposophy on Hába manifested in various aspects of his activities. He was guided by its principles in his approach to other people, demonstrating openness toward individuals of different faiths and convictions. Anthroposophy inspired also his own musical theory and practice. Moreover, his conception of socialism, shaped by Rudolf Steiner's anthroposophical ideas, differed significantly from the Soviet vision of socialist realism.
After World War II, at the end of the 1940s, despite Hába's previous engagement with the Soviet Union, his political and aesthetic views began to be perceived as ideologically unreliable. Consequently, he spent the last 20 years of his life as an independent artist.
In December 1934 they signed a joint protocol (Protokoll der Besprechung) concerning an agreement between ISCM’s Slav sections, which were to cooperate on ensuring an adequate representation of Slav music at festivals, artistic exchange, and organisation of contemporary Slav music festivals. In 1936–37 Koffer and Hába jointly drafted the ISCM’s new statute. Privately they were friends. In 1936 Koffler dedicated to Alois’s daughter Miluška a cycle of 'light piano pieces.' Koffler’s letter to Hába of December 1938 contains one of the few traces of Róża Koffler’s presence in the form of her handwritten greetings for Alois’s family in a postscript. It was thanks to Hába’s efforts that Koffler’s Symphony No. 3, Op. 21 was included in the programme of the ISCM festival in London. The surviving correspondence between the two composers consists of thirteen letters and postcards, now kept at the Czech Museum of Music (České muzeum hudby) in Prague.